1. Field of the Invention
The present invention is directed to a protective arrangement for an implantable defibrillator of the type having jacks or sockets for the electrical and mechanical connection of electrode leads to the housing.
2. Description of the Prior Art
As is known, implantable defibrillators contain a high-voltage generator arranged in the housing of the defibrillator, which generates a high-voltage pulse at the connecting jacks or sockets on demand. This pulse is then delivered to the heart to be defibrillated via lead terminating electrodes disposed at or in the proximity of the heart. The demand for delivering a high-voltage output pulse can ensue automatically after evaluating mensurationally acquired physiological parameters that indicate a fibrillation condition of the heart or can ensue proceeding extracorporeally outside via a programming device, for example for testing purposes.
In order to prevent a person handling the defibrillator during manufacture, and later in conjunction with the implantation of the defibrillator, from receiving an electrical shock due to some kind of fault, a protective arrangement is disclosed herein for an implantable defibrillator of the type described above which includes a plug part, with terminal pins, that is detachably connectable to the defibrillator housing, these terminal pins being insertable into the connecting sockets while producing an electrically conductive connection and being directly connected to one another via an electrical resistor inside the plug part.
A generally similar plug part for a heart pacemaker is disclosed in U.S. Pat. No. 4,830,005, however, in that known plug a resistor is arranged between the terminal pins in series with a magnetic switch, the magnetic switch being capable of being closed for testing purposes with an external testing magnet. This known plug thus does not represent protection against high-voltage but is instead for simulating the heart impedance using the resistor in order to be able to test the heart pacemaker for functionability before an implantation. A high-voltage protection is not achieved with this known arrangement because the magnetic switch is not opened in the normal case.
An arrangement is disclosed in U.S. Pat. No. 3,998,542 composed of a resistor cascade with a glow lamp as a display element for testing the output energy of defibrillators. This known test circuit has contact surfaces against which the electrodes of the defibrillator are planarly applied in order to subsequently trigger the output of a high-voltage pulse by the defibrillator. Again, no high-voltage protection whatsoever is provided.